1. Field of the Invention
This invention relates broadly to stereo speakers. More particularly, this invention relates to lightweight, portable stereo speakers.
2. State of the Art
Sound quality is important in the design of sound reproducing systems, such as speakers used in concert halls, home stereo systems, and portable stereo systems. Further, size, shape, weight, and portability are also important. The size and shape and ultimate weight of the entire stereo system is often driven by the speaker sound quality requirements. Sound quality and other acoustical resonance related characteristics are enhanced by having an enclosed air volume behind the speaker driver. In general, the optimal size of the enclosure will depend on the size of the speaker driver. Generally, for space and weight constrained sound systems including boomboxes and portable stereos, the smaller speaker drivers are mounted within a relatively small housing or enclosure which provides less than ideal quality sound reproduction. To improve the sound quality, using a larger driver, and hence enclosure is preferable. For large high-fidelity speaker drivers i.e., those used for public address, concert, or stadium sound systems, optimal quality sound reproduction requires using relatively large high-fidelity speaker drivers and mounting them within relatively large enclosures. Toward this end, large high fidelity speaker drivers are generally mounted within large rectangular substantially hollow boxes formed from wood, pressed board, or hard plastic. Although such enclosures are quite sturdy, they are generally heavy, bulky, and cumbersome. Further, they often require great strength and effort to move and install, and require sturdy supports to mount on speaker stands. When used in touring events, these large speaker systems can require numerous trucks to transport them from event to event. When not in use, they require a large storage facility. Collapsible speaker enclosures have been designed which alleviate some of the bulkiness and difficulties related to storage and transport of these large speaker assemblies. However, the weight of the collapsible speaker assemblies remain the same whether in the extended or collapsed state.
It is therefore an object of the invention to provide a portable speaker assembly which is lightweight, portable, and easily mountable and which has good sound quality.
It is another object of the invention to provide a portable speaker assembly which requires minimal freight or storage volume yet which has a desirable air chamber volume behind the speaker.
It is a further object of the invention to provide a portable speaker assembly having an expandable bladder which expands to form a desired shape and size substantially forming the exterior of the speaker enclosure.
It is an additional object of the invention to provide a portable speaker assembly having a vacuum deflatable bladder formed from a material having a memory for an expanded shape once the vacuum is removed.
It is yet another object of the invention to provide a portable speaker assembly which has fire retarding properties.
In accord with these objects, which will be discussed in detail below, a speaker assembly includes a rigid front speaker mounting element, at least one speaker driver coupled to the speaker mounting element, a flexible bladder coupled to the speaker mounting element, and a valve coupled to the flexible bladder. The bladder preferably is formed having a first wall portion and a second wall portion defining a substantially air-tight interior space therebetween. The bladder is preferably formed from a flexible, puncture resistant or healable material which can withstand repeated cycles of inflation and deflation and which may be formed to take any desired shape when inflated. Together, the rigid front speaker mounting element and the flexible bladder form an enclosure defining at least one interior chamber at least partially surrounding the speaker driver. The valve, which provides a substantially air-tight seal when closed, is in fluid communication with the interior space of the flexible bladder and is used for inflation and deflation of the bladder.
According to one embodiment of the invention, the flexible bladder is inflatable by providing either pressurized gas or expandable foam within the interior space of the inflatable flexible bladder. Additionally, a fire retarding powder or fire retarding gas may also be introduced within the flexible bladder. According to additional embodiments of the invention, the inflatable speaker enclosure assembly may include preferred aspects such as a sound port for improved low frequency sound transmission, internal or external tension straps to prevent over-inflation, internal structural support ribs for cross-bracing, and multiple bladders for structural strength. Further, the flexible bladder may be formed as a multi-celled bladder which prevents deflation of the entire speaker enclosure in the event one cell is damaged. Additional embodiments may include a rigid rear member coupled to the inflatable bladder opposite the rigid front speaker mounting element which may be ported thereby providing an opening between the interior chamber and an exterior environment.
According to another embodiment, the speaker enclosure assembly may further include a hard-shell substantially enclosing the flexible bladder. The housing is designed to resemble a typical hard-shelled speaker enclosure case and may be designed to break down into flat boards. When inflated, the flexible bladder is disposed substantially along an internal perimeter of the shell.
According to yet another embodiment, the flexible bladder is deflatable by providing a vacuum to evacuate any gas contained within the interior space of the flexible bladder. Until released from vacuum, the bladder maintains its evacuated state. The bladder is preferably formed from a material having a memory for the expanded shape such that once released from vacuum, the bladder reassumes a desired expanded shape and size. Alternatively, the bladder may instead contain memory expanding material such as expandable open-celled foam or polyester batting.
Additional objects and advantages of the invention will become apparent to those skilled in the art upon reference to the detailed description taken in conjunction with the provided figures.